val responseA = client.newCall(requestA).execute()

    assertThat(responseA.body.string()).isEqualTo("a")
    assertThat(server.takeRequest().sequenceNumber).isEqualTo(0)

    // Give the socket a chance to become stale.
    connection!!.idleAtNs -= IDLE_CONNECTION_HEALTHY_NS
    Thread.sleep(250)

    val requestB =
      Request(
        url = server.url("/"),

   * This avoids sending potentially sensitive data like HTTP cookies to the proxy unencrypted.
   *
   * In order to support preemptive authentication we pass a fake "Auth Failed" response to the
   * authenticator. This gives the authenticator the option to customize the CONNECT request. It can
   * decline to do so by returning null, in which case OkHttp will use it as-is.
   */
  @Throws(IOException::class)

is what we're calling our implementation of Happy Eyeballs, [RFC 8305][rfc_8305]. With this
feature OkHttp will attempt both IPv6 and IPv4 connections concurrently, keeping whichever connects
first. Fast fallback gives IPv6 connections a 250 ms head start so IPv6 is preferred on networks
where it's available.

To opt-in, configure your `OkHttpClient.Builder`:


```
OkHttpClient client = new OkHttpClient.Builder()

        )
          .redirectInput(File("/dev/null"))
          .redirectOutput(File("/dev/null"))
          .redirectError(Redirect.INHERIT)
          .start().also {
            // Give it time to start collecting
            Thread.sleep(2000)
          }
      }
    }

    return null
  }

  class WireSharkKeyLoggerListener(
    private val logFile: File,

            @Throws(IOException::class)
            override fun authenticate(route: Route?, response: Response): Request? {
              if (response.request.header("Authorization") != null) {
                return null // Give up, we've already attempted to authenticate.
              }

              println("Authenticating for response: $response")
              println("Challenges: ${response.challenges()}")

    val charset = parameter("charset") ?: return defaultValue
    return try {
      Charset.forName(charset)
    } catch (_: IllegalArgumentException) {
      defaultValue // This charset is invalid or unsupported. Give up.
    }
  }

  /**
   * Returns the parameter [name] of this media type, or null if this media type does not define
   * such a parameter.
   */
  fun parameter(name: String): String? = commonParameter(name)

Upgrading to OkHttp 4
=====================

OkHttp 4.x upgrades our implementation language from Java to Kotlin and keeps everything else the
same. We’ve chosen Kotlin because it gives us powerful new capabilities while integrating closely
with Java.

We spent a lot of time and energy on retaining strict compatibility with OkHttp 3.x. We’re even
keeping the package name the same: `okhttp3`!

There are three kinds of compatibility we’re tracking:

        .build()
    val request = Request(server.url("/"))
    val response1 = client.newCall(request).execute()
    assertThat(response1.body.string()).isEqualTo("a")

    // Give the thread pool a chance to evict.
    Thread.sleep(500)
    val response2 = client.newCall(request).execute()
    assertThat(response2.body.string()).isEqualTo("b")

      Work or Derivative Works thereof in any medium, with or without
      modifications, and in Source or Object form, provided that You
      meet the following conditions:

      (a) You must give any other recipients of the Work or
          Derivative Works a copy of this License; and

      (b) You must cause any modified files to carry prominent notices
          stating that You changed the files; and

   *
   * ```
   *   attackerCa
   *     -> attackerIntermediate
   *         -> phonyVictim
   * ```
   *
   * Some implementations fail the TLS handshake when they see the long chain, and don't give
   * CertificatePinner the opportunity to produce a different chain from their own. This includes
   * the OpenJDK 11 TLS implementation, which itself fails the handshake when it encounters a non-CA
   * certificate.
   */